Galactic Cannonball Heading Our Way

Astronomers have known about celestial objects called globular clusters for centuries. They’re collections of maybe 100,000 stars, tightly bunched into a roughly spherical configuration, which orbit the central part of the Milky Way and other galaxies in a relatively lazy fashion, like a swarm of laid-back bees.

But observers have spotted one such cluster that’s behaving extremely strangely. This one is located in the vicinity of M87, a gigantic, blob-shaped galaxy—at least ten times as massive as the 300 billion star Milky Way—which lies about 53 million light years from Earth. The cluster doesn’t seem to be orbiting, and it’s anything but lazy: instead, it’s speeding in our direction at a blistering 2 million m.p.h., (3.2 million k/h) as though it’s been flung from its home galaxy like a bullet—except much, much faster. “We’ve found speeding, runaway stars before,” says Harvard astronomer Nelson Caldwell, who co-discovered this bizarre object. “But…